The Origin of Species by Means of Natural Selection, Or, The Preservation of Favoured Races in the Struggle for LifeG. Richards, 1902 - Всего страниц: 454 |
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... structures variable- Parts developed in an unusual manner are highly variable : specific characters more variable than ... structure with changed functions - Widely different organs in members of the same class , de- veloped from one and ...
... structures variable- Parts developed in an unusual manner are highly variable : specific characters more variable than ... structure with changed functions - Widely different organs in members of the same class , de- veloped from one and ...
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... structure not necessarily simultaneous - Diffi- culties of the theory of the Natural Selection of instincts - Neuter or sterile insects — Summary 346 ADDITIONS AND CORRECTIONS TO THE SIXTH EDITION Numerous small corrections 6 CONTENTS.
... structure not necessarily simultaneous - Diffi- culties of the theory of the Natural Selection of instincts - Neuter or sterile insects — Summary 346 ADDITIONS AND CORRECTIONS TO THE SIXTH EDITION Numerous small corrections 6 CONTENTS.
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... structure and coadaptation which justly excites our admiration . Naturalists contin- ually refer to external conditions , such as climate , food , etc. , as the only possible cause of variation . In one limited sense , as we shall ...
... structure and coadaptation which justly excites our admiration . Naturalists contin- ually refer to external conditions , such as climate , food , etc. , as the only possible cause of variation . In one limited sense , as we shall ...
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... structure so strongly pronounced as to de- serve to be called monstrosities arise ; but monstrosities cannot be separated by any distinct line from slighter variations . All such changes of structure , whether ex- tremely slight or ...
... structure so strongly pronounced as to de- serve to be called monstrosities arise ; but monstrosities cannot be separated by any distinct line from slighter variations . All such changes of structure , whether ex- tremely slight or ...
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... structure and constitution in which the varieties and sub - varieties differ slightly from each other . The whole organisation seems to have become plastic , and departs in a slight degree from that of the parental type . Any variation ...
... structure and constitution in which the varieties and sub - varieties differ slightly from each other . The whole organisation seems to have become plastic , and departs in a slight degree from that of the parental type . Any variation ...
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adapted admit affinities allied species America analogous ancient animals appear beak become bees believe belonging birds breeds cause cells characters climate closely allied color common continent crossed crustaceans degree developed difficulty distinct species domestic doubt effects eggs embryo existing extinct extremely facts favorable fertility fishes flowers formation forms fossil Fritz Müller genera genus geological Glacial period gradations greater number groups of species habits Hence hybrids important individuals inhabitants inherited insects instance instincts intercrossing intermediate kind lamellæ larvæ less living Malay Archipelago male mammals manner marsupial migration modified descendants natural selection naturalists nearly nest offspring organs paleozoic parent peculiar perfect pigeon pistil plants pollen present principle probably produced progenitor quadrupeds ranked reciprocal crosses remarked resemblance rudimentary seeds sexual selection Silurian slight South America stamens sterility structure successive supposed tend theory tion trees variability variations varieties vary whole wings young
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Стр. 21 - In the distant future I see open fields for far more important researches. Psychology will be based on a new foundation, that of the necessary acquirement of each mental power and capacity by gradation. Light will be thrown on the origin of man and his history.
Стр. 279 - If it could be proved that any part of the structure of any one species had been formed for the exclusive good of another species, it would annihilate my theory, for such could not have been produced through natural selection.
Стр. 147 - Every species has come into existence coincident both in space and time with a pre-existing closely allied species.
Стр. 121 - If such do occur, can we doubt (remembering that many more individuals are born than can possibly survive) that individuals having any advantage, however slight, over others, would have the best chance of surviving and of procreating their kind ? On the other hand, we may feel sure that any variation in the least degree injurious would be rigidly destroyed. This preservation of favourable individual differences and variations, and the destruction of those which are injurious, I have called Natural...
Стр. 255 - If it could be demonstrated that any complex organ existed which could not possibly have been formed by numerous, successive, slight modifications, my theory would absolutely break down.
Стр. 132 - ... perform strange antics before the females, which, standing by as spectators, at last choose the most attractive partner.
Стр. 316 - There is grandeur in this view of life, with its several powers, having been originally breathed by the Creator into a few forms or into one; and that, whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being evolved.
Стр. 58 - We cannot suppose that all the breeds were suddenly produced as perfect and as useful as we now see them ; indeed, in several cases, we know that this has not been their history. The key is man's power of accumulative selection : nature gives successive variations ; man adds them up in certain directions useful to him.
Стр. 122 - So again it is difficult to avoid personifying the word Nature; but I mean by Nature, only the aggregate action and product of many natural laws, and by laws the sequence of events as ascertained by us.
Стр. 316 - Thus from the war of nature, from famine and death, the most exalted object which we are capable of conceiving — namely, the production of the higher animals — directly follows. There is grandeur in this view of life, with its several powers, having been originally breathed by the Creator into a few forms or into one...